African Union (AU) peacekeepers directly intervened for the first time to support government forces.

But a spokesman for the AU force, whose remit allows them only to protect government buildings and defend themselves if attacked, told Al Jazeera that the troops actions were a "show of force" rather than combat engagement.

An Associated Press reporter saw several bodies and two AU tanks on the front line Sunday.

Government forces used rocket-propelled grenades and anti-aircraft guns mounted on the back of lorries, which they fired horizontally through the streets.

Sporadic gunfire could still be heard late into the night following the fighters' retreat.

Various armed groups, some of them allegedly linked to al-Qaeda, have been fighting the UN-backed government since being chased from power over two years ago.

Mogadishu sees near-daily battles between government force and the fighters, with thousands of civilians killed in recent years.